I had this fantasy a lot, and the most common involves all the animals on earth turning into Pokemon. And since humans did exist in Pokemon, we humans remained the same.

Since I live on a farm, I took the liberty of figuring out what pokemon would end up there:

I had Sheep (Mareep, Flaafy), goats (Ampharos, I know it is the evolution, but if you see a goat trying to climb a gate door, you'll see the resemblance every time.), Pigs (I was going to say Spoink or Grumpig, but I have to say Swinub, mainly because of the other animal we have on our farm), Yaks (Piloswine, which means we would have to have the baby forms as well, which would be piglets, though I do believe that we must have at least one Grumpig, as he have two very adult Pigs on our farm as well.) Chickens (Torchic and Combusken), Ducks (Ducklett), Geese (Swanna, my call because we don't have a goose pokemon, and it makes sense as to why our geese raise our ducks like their own babies.) Two dogs (A growlith and a Mightyana (Different species)), and a swarm of Meowths and skitties and their evolved forms.

My story when I would do these things was that I would take a young Swinub with me after the world got turned into Pokemon, in hopes of finding out what other Pokemon live out there. I soon come across a Cubone and an elekid and learn about how there is a small community growing already of Trainers who want to be the best because they can now make a living off of Pokemon.

Of course, when I get there I make it a point that even if we adopted the economy of Pokemon, it wouldn't work. As we would need to rebuild our entire infrastructure around Pokemon, and the rest of the world wasn't ready for such change. not to mention the problems with the whole free health care for Pokemon thing. And the PETA would have a huge fit about the glorification of dog fighting.

And my memory stops there as I usually start daydreaming about the possibilities of a Luigi game